Fluid pressure producing device



' Nov. 23, 1-943. E. F. LOWEKE FLUID PRESSURE PRODUCING DEVICE Filed Feb. 17, 1 41 v7 2 5'. Z. v I v INVENTOR.

[em/v F Loner/r:

QTTOE/VEV Patented Nov. l

; UNIT-ED sTArss PATENT orr cs Erwin F. Lowek e,

draulic Brake Company, poration o1 Californi Application February 17,

1 Claims. (01. era-54.6)

This invention relates to fluid pressure produc ing devices, and more particularly to improvements inthe construction and assembly of parts thereof.

A primary object a new and improved form oi. compound cylinder of light and compact design and short length adapted to be manufactured in quantities and at a reasonable cost.

Another object of the invention is the provision of a fluid pressure producing device having low and high pressure chambers Iormed largely of tubing.

Another object of the invention is to provide a fluid pressure device including a compound cylinder formed of sheet metal tubing, die castings, and stampings.

Another object of the of a fluid pressure producing device including a compound cylinder comprising two concentric sheet metal tubes arranged one within and spaced from the-other. One pressure chamber is provided within the inner'tube and a second pressure chamber is provided between the two tubes.

The two tubes are closed with a common end piece or head having concentric flanges which seat-the tubes. Another object of the invention is the prevision oi a fluid pressure producing device including a cylinder having a piston reciprocable therein and having a flexible boot secured at one end to the piston and at the opposite end to the cylinder, closing such end of the cylinder and forming a iiuid chamber therein between the boot and the. piston. The construction is such that the chamber formed between the boot and the piston communicates with the chamber within the opposite end of the cylinder, and as here shown through the piston. The boot chamber also communicates, through an annular chamber formed within the piston contiguous the cylinder, with a fluid reservoir.

Another object 01! the sion of a compound cylinder having a large piston and small piston with the. pistons arranged in such a manner within the cylinder that the heads of the two pistons lie substantially in the same transverse plane within the cylinder.

A iurther object or the invention is the provi-' slon or a compound cylinder having its low pressure cylinder and its high pressure cylinder arranged'one' within the other and whereby the chamber or the low pressure cylinder surrounds the cylinder which forms the hill! pressure chainoi the invention is provide invention is the provision Detroit, Mich, asslgnor to Hy Detroit, Micln, a cor- 1941, Serial Nb. 379,360

A feature of the construction is that the low pressure piston which operates within the space between the two cylinders is hollow or annular in shape and the high pressure cylinder'telescopes thereinto during the compression stroke and the high pressure piston is disposed interiorly of the low pressure piston.

Other objects and will appear from the following description taken in connection with the drawing forming a part of the specification, and in which- Fig. 1 is a vertical sectional view of the fluid pressure producing device} Fig. 2 is a sectional view 2-2 of Fig. 1; and Fig. 3 is a sectional 3 -3, Fig. 1.

substantially on line view substantially on line Referring to the drawing for more specific deinders are open at their opposite ends. Head Mr is provided with concentrically disposed axial flanges I2 and 24 for i'lrmly seeming the cylinders l2 and H thereto. The head It has a discharge port 28 interiorly threaded to receive an outlet pipe, not shown, and is .further provided with a circumferential flange "for suitably fastening the cylinder assembly III to the chassis oi an automotive vehicle. These cylinders are thinwalled and or light weight, as would be the case invention is the proviit formed of sheet metal tubes, and hereinafter where the word tubular is used todescribe the cylinders, such characterization is intended. Mind to the cylinder I0 is a suitable connection 30, normally connected to a conventional fluid tank,'nct shown. Connection 30 has therethrough a port 32 communicating with the chamber 20 by way of passages 34 and 38..

Fitted on the open end of cylinder I2 is a sleeve I having an annular shoulder 40 abutting the end o! the cylinder. An annular groove 42 in the cylinder III communicates with the chamber 20 by way of ports I in the sleeve 88 and with the chamber ll by way of .a line passage formed by the shoulder ll of the sleeve and the end of the cylinder It. The passage .the irregularity inherent in rough machining of the abutting end-o! the'sleeve. The sleeve has .an extension ll provided with advantagesiof the invent-ion ll is obtained by a bore ll con- A plug is interposed between supported by a retaining ring 60 fitted on the open end of the cylinder I4. The piston has a head 62, a reduced body portion 64, and an in- An annular-chamber 60 is ternal portion 66. formed between the cylinder wall and the reduced body portion 64, the flange 56, and head 62 of the piston. This chamber communicates through port 34 andpassageway 32 with the fluid chitmber of a tank,not shown.

provides in conjunction with the internal portion 66 of the piston a chamber 12. Ports 14 in the portion 66 provide'communication between the chamber 12 and a chamber I6 rearward, of the flange 56 on the. piston 54. This chamber I6 is completed by a boot 86. A groove 80 in the plug- I0 cooperates with a groove 62 in the internal portion 66 of the piston so as to securely hold a rib'8 4 of the flexible boot 86 to secure one end of the boot to the piston. other end of the boot is ribbed and provided with openings therethrough so as .to fasten the boot to the retaining ring 60 by means of bolts 86.

The chamber 'I6'formed by the boot 66 and pis- 1 ton flange 56 communicates with the annular chamber 66 by way of a plurality of ports 90 in the flange 56. The chamber 12 communicates through a ball check controlled bore I8 with the interior of piston 54 and the low pressure chamber.-

Plug 'I0has a recess formed in its back for the reception of a round-headed pin 92 fitted in the end of a tubular thrust rod 9%. A forward end 96 of the plug centers in the chamber 12.

The head 62 of the large piston 54 has a plurality of ports or passages 68 providing communication between the annular chamber 66 and that potion of the large-chamber ,I8-forward. of the head 62, and a sealing cup I00 is seated on the head for control of the passages. A spring I02 the sealing cup and head I6 of the cylinder I0 and. serves to retain the sealing cup against the piston to its retracted position.

The small cylinder I2 with its end ieev'eja.

The

displacement and to return ways I I6 also establish communication between an extension chamberand the chamber I2 through the bore 16. I

Within the chamber 12 is a ball. valve II 8 normally held by a spring I 20 to close the bore I6. A plunger I22reciprccable the bore IIO has a head I24 abutting the sealing cup I06 and I26 extending through the bore 18 and bearing against the ball valve II8.

In a normal ope-ration of the fluid pressure producing device,- mechanism, not shown, force is transmitted therefrom through the thrust pin 94 and pin 92, resulting in forward movement of the pistons 52 and 54 on their compression strokes.

During the initial movement of the pistons 52 and 54 on the compression stroke, the sealing which forms the high pressure chamber extends 7 into the hollowed-out large piston 54 spaced therefrom whereby during reciprocation over the cylinder I2. The internal portion 66 of the large piston 54 has an external diameter less than the inside diameter of cylinder I2 to enter therein.

The small piston 52 reciprocable in the chamber I8 has a head I04 provided with a plurality of passages I05 therethrough providing communications between the chamber I8 within the cylinder I2 and the chamber 20 within the cylinder I4 outside of the cylinder I on the piston head I04 controls the passages I05 and is held against displacement ,by a spring I08, interposed between the sealing cup I06 and the head I6 or the cylinder I0. This spring also serves to return the piston to its retracted position. I This head has a rearward extension Ill provided with a concentric bore H2, and an end 4 which abuts the internal portion 66 or the piston 54. Gland passages II6 through the end portion, Ill establish communication between the bore 2 and the chamber 20. Such passage.

the large piston telescopes I I2. A sealing cup I06 cup I00 on the large piston 54 closes the port 36 through cylinder wall I4 and'the sealing cup I06 on the small piston 52 .closes theline passage 46 between chambers I6 and 20. Thereafter, as the pistons advance, fluid in the chamber20 is displaced therefrom through the passages I05 in the piston 52, past the sealing cup I06 into the chamber port 26' into fluid pressure delivery pipes, not shown, for delivery to a suitable mechanism, not shown, requiring fluid pressure.

As the pistons are further advanced, as pressure needs require, the ball valve II8 loaded to a predetermined pressure cracks, due to the fluid pressure on the sealing cup I06 being transmitted through the head I26 of the plunger I22 and its extension I26, thereby unseating the ball. The fluid pressure in the large chamber 20 of the cylinder is thereby relieved and a portion of the fluid isreturned from the large chamber 20 through the chamber [2 through the passages I4, the chamber 16, passages '90, annular chamber 66, port 34 and the port 30 into aconventional reservoir or tank, not shown.

Upon release of the applied force, suitable spring means undisclosed return the thrust rod to its retracted position allowing the pistons 52 and 54-to return totheir-retracted positions under the influence of springs I02 and I08. During this operation, the spring I20 moves the valve II6 to its closed position and piston 54 uncovers port 36 establishing fluid communication between chamber-20 and the fluid reservoir, not shown. Piston 52 uncovers the line ing fluid communication and chamber 20.

As the pistons 52 and 54 return to their retracted positions, a partial vacuum is created in the chamber I0, and this results in from the reservoir or tank through the port 34, into the annular chamber 68, thence through the passages '98 in the head of the piston 54, past the sealing cup I00 thereon into the chamber 20, thence through the passages I05 in the piston 52, and. past the sealing ,cup I06 thereon into the chamber I 8, l0 and 20.

with the return anism requiring fluid pressure, the chamber I8 may be in receiptfof a. quantity of fluid in excess of its capacity, and under this condition the exbetween I chamber I8 While this invention has been described in connection with certain specific embodiments, the .m'inciple involved is susceptibleof numerous upon actuation of a suitable I8, thence through the discharge p s e 46 establishcompletely' filling the chambers of the fluid from the mech-- ation thereof having reciprocable therein when in sons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims. I

I claim:

1. In the construction of a compound cylinder,

/ a pair of tubular spaced concentric cylinders head common to both closed at one end by a cylinders and open at their other end, pistons reciprocable in their respective cylinders, and a sleeve fitted on the inner cylinder including a part extended beyond the cylinder of equal diameter to the interior of the cylinder adapted to support the piston reciprocable in the inner cylinder and providing in conjunction with the inner cylinder a communication between the cylinders when the piston is in retracted position.

2. In the construction of a compound cylinder, a pair of tubular spaced concentric cylinders, a head common to the two cylinders having axially disposed concentric flanges engaging the cylinders therewith the inner cylinder having an annular groove at its open end, and a sleeve including a partembracing the inner cylinder having ports therethrough communicating with the annular groove and a part coextensive with the cylinder spaced from provide communication between the cylinders by way of the groove and po 3. In the construction of a compound cylinder, 0. pair of tubular spaced concentric cylinders secured at their'one end in a vertical plane to a common end plate on axially disposed concen-z tric flanges iorming part of the end plate, pistons reciprocable lnthe respective cylinders the cylinder oi the-larger diameter being substantially longer than the cylinder of lesser diameter and braced at its other end by a circumferential ring, and the smaller cylinder embraced by a sleeve fitted on its other end and providing a continuthe same internal diameter, said sleeve adapted to support the piston its retracted position.

4. In the construction 01' a compound cylinder, a pair 'cylindersof unlike diameters, a head for the cylinders having concentric axially extended flanges thereon, head concentric the flanges, means on the head for stationary attachment or the cylinder, pisthe open end thereof to a port through thetons reciprocable a sleeve fitted on the smaller cylinder providing in conjunction therewith a communication between the cylinders when the pistons are in retracted position.

5. In a fluid pressure headsecured thereon defining a large chamber and a small chamber, pistons reciprocable inthe respective chambers, and a. sleeve having a part embracing the openend oi the small cylinder providing in conjunction with the small cylinder a communication between the chambers.

6. In a fluid pressure producing device, a cylinder closed at one end by a head, piston mechanism reclprocable within the cylinder defining a compression'chamber therein between the piston and the cylinder head and having an annular chamber adiacent'the cylinder wall, a flexible boot extending between the piston mechanism and the adjacent end of th cylinder defining a fluid chamberat such end or the cylinder between the boot and the piston,- said piston having a passageway adjacent the end or the boot con,- nected to the piston mechanism establishing fluid communication her and said compression chamber, passages through the piston adjacent the end '0! the boot connected to the cylinder providing communication between the fluid chamber and I annular chamber, and a fluid intake into the cylinder communicating with the compression chamber at one end or the piston and with the'annular chamher at the opposite end of the piston.

'7. A device of the class described comprising a cylinder, a piston reciprocable in the cylinder, said piston having an inner portion and an annular chamber adjacent the cylinder wall, a plug secured in the inner portionoi the piston and deflning a chamber therein, a flexible boot secured at one end of the piston by the plug and secured at the other end to the'cylinder establishing a chamber between the piston and boot. passages in thepiston providing communication between the boot chamber and the annular chamber, and ports in the piston providing communication between the boot chamber and the chamber within the piston.

' mm 1. LOWEKIE.

in the respective cylinders, and

producing device com-- 7 prising spaced concentric cylinders closed at one end by a common between said fluid cham-' 

